Hi Arnie and Welcome to WS !!
There was a lot of discussion of the two different models much earlier on the forum. As far as we know, the incinerator that was found on the farm was the SN250, not the SN500. The reason for the confusion is that the Globe & Mail made reference to the SN500 (but did not state that it was found on the farm). The Sun specifically referenced the SN250 as having been found on the farm.
see AD's post at:
Websleuths Crime Sleuthing Community - View Single Post - The Incinerator
Sorry I don't have time to find the specs on the SN250 right now, but they will be in the threads somewhere (just do a forum search for the term SN250).
IIRC, the main difference was the smaller opening on the SN250 and capacity of 250 lbs.